Transactions of the Korean Society of Mechanical Engineers B (대한기계학회논문집B)

The Korean Society of Mechanical Engineers (대한기계학회)
권호 표지
DOI QR코드

DOI QR Code

Effect of Stent Design Porosity on Hemodynamics Within Cerebral Aneurysm Model: Numerical Analysis

스텐트 공극률의 뇌동맥류 모델 내부 유동장 영향 수치해석

  • Received : 2013.08.06
  • Accepted : 2013.10.28
  • Published : 2014.01.01
Download PDF
⟨ Previous Next ⟩

Abstract

In the present study, CFD simulations were conducted for investigating intra-aneurysmal flow characteristics with different stent porosities ($C_{\alpha}$ = 80%, 74%, and 64%), and the simulation results were compared with experimental data. Using a quadratic tetrahedral element-based finite element scheme, we estimated velocity fields and wall shear stress. The intra-aneurysmal velocity reduction ratios obtained via simulation agree well with published experimental data. It was found that a stent with a porosity of 80%, which is highest in the present study, is able to effectively reduce flow into the aneurysm, which causes intra-aneurysmal stasis, and that stents with lower porosities afford only incremental benefits in reducing inflow to an aneurysm.

본 연구에서는 상대적으로 얇은 두께의 스트럿을 가진 스텐트를 적용하여 스텐트의 공극률(80%, 74% 및 64%)에 따른 뇌동맥류 내부 유동 특성 변화를 이해하고자 CFD 해석을 수행하고, 기존의 발표된 실험 결과와 비교하였다. 수치해석 방법으로는 이차의 사면체 요소(quadratic tetrahedral element) 기반의 유한요소해석(FEM) 코드를 이용하였다. 뇌동맥류 내부 평균유속 감소비의 정량적인 면에서는 실험결과와 약간의 차이를 보였으나, 스텐트 공극률에 따른 뇌동맥류 내부 유동장 패턴 및 평균유속 감소의 상대적 특성 등은 비교적 잘 일치하는 것을 확인할 수 있었다. 또한 본 연구에서 고려한 가장 높은 80% 공극률을 가지는 스텐트의 경우에도 비교적 우수한 뇌동맥류 유입 유속 감소 효과를 가짐을 확인할 수 있었으며, 이보다 더 낮은 공극률을 가진 스텐트의 경우에는 약간의 추가적인 뇌동맥류 유입 유속 감소 효과를 가지나, 유속 및 벽전단응력 등의 혈류역학적 특성은 큰 변화가 없음을 알 수 있었다.

Keywords

References

  1. Rinkel, G., Djibuti, M., Algra, A. and van Gijn, J., 1998, "Prevalence and Risk of Rupture of Intracranial Aneurysms: A Systematic Review," Stroke, Vol. 29, pp. 251-256. https://doi.org/10.1161/01.STR.29.1.251
  2. Wiebers, D., Whisnant, J., Huston, J., Meissner, I., Brown, R., Piepgras, D., Forbes, G. and Thielen, K., et al., 2003, "Unruptured Intracranial Aneurysms: Natural History, Clinical Outcome, and Risks of Surgical and Endovascular Treatment," Lancet, Vol. 362, pp.103-110. https://doi.org/10.1016/S0140-6736(03)13860-3
  3. Ishibashi, T., Murayama, Y., Urashima, M., Saguchi, T., Ebara, M., Arakawa, H., Irie, K., Takao, H. and Abe, T., 2009, "Unruptured Intracranial Aneurysms: Incidence of Rupture and Risk Factors," Stroke, Vol. 40, pp. 313-316. https://doi.org/10.1161/STROKEAHA.108.521674
  4. Valencia, A., Guzmán, A., Finol, E. and Amon, C., 2006, "Blood Flow Dynamics in Saccular Aneurysm Models of the Basilar Artery," J. Biomech. Eng. Vol. 128, pp. 516-526 https://doi.org/10.1115/1.2205377
  5. Steinman, D., Milner, J., Norley, C., Lownie, S. and Holdsworth, D., 2003, "Image-Based Computational Simulation of Flow Dynamics in a Giant Intracranial Aneurysm," AJNR Am. J. Neuroradiol., Vol. 24, pp. 559-566.
  6. Sforza, D., Putman, C., Scrivano, E., Lylyk, P. and Cebral, J., 2010, "Blood-Flow Characteristics in a Terminal Basilar Tip Aneurysm Prior to Its Fatal Rupture," AJNR Am. J. Neuroradiol., Vol. 31, pp. 1127-1131. https://doi.org/10.3174/ajnr.A2021
  7. Park, J.S. and Lee, S.W., 2011, "Effects of non-Newtonian Fluid Model in Cerebral Saccular Aneurysms," J. Comp. Fluids Eng., Vol. 14(3), pp. 81-87.
  8. Lee, S.W., 2012, "On the Effect of Shear-Thinning Rheology on Hemodynamic Characteristics in Basilar Tip Aneurysms with Implication of Two Distinct Flow Patterns," JMST, Vol. 26(10), pp. 3125-3132.
  9. Kim, M., Taulbee, D.B., Tremmel, M. and Meng, H., 2008, "Comparison of Two Stents in Modifying Cerebral Aneurysm Hemodynamics," Ann. Biomed. Eng., Vol. 36(5), pp. 726-741. https://doi.org/10.1007/s10439-008-9449-4
  10. Liou, T.M. and Li, Y.C., 2008, "Effects of Stent Porosity on Hemodynamics in a Sidewall Aneurysm Model," J Biomech., Vol. 41, pp. 1174-1183. https://doi.org/10.1016/j.jbiomech.2008.01.025
  11. Kim, Y.H., Xu, X. and Lee, J.S., 2010, "The Effect of Stent Porosity and Strut Shape on Saccular Aneurysm and Its Numerical Analysis with Lattice Boltzmann Method," Ann Biomed Eng. Vol. 38, pp. 2274-2292 https://doi.org/10.1007/s10439-010-9994-5
  12. Yu, C. H., Matsumoto, K., Shida, S., Kim, D. J. and Ohta, M., 2012, "A Steady Flow Analysis on a Cerebal Aneurysm Model with Several Stents for New Stent Design Using PIV," JMST, Vol. 26, No. 5, pp. 1333-1340.
  13. Ethier, C., Prakash, S., Steinman, D., Leask, R., Couch, G. and Ojha, M., 1999, "Steady Flow Separation Patterns in a 45 Degree Junction," J. Fluid Mech., Vol. 411, pp. 1-38.
  14. Minev, P. and Ethier, 1998, "A Characteristic/ Finite Element Algorithm for the 3-D Navier- Stokes Equations Using Unstructured Grids," Comp. Meth. App. Mech. Eng., Vol. 178, No. 1-2, pp. 39-50. https://doi.org/10.1016/S0045-7825(99)00003-1